Definition
A pre-programmed set of actions that an unmanned aircraft automatically performs when the command-and-control radio link between the aircraft and its remote pilot is lost. The procedure typically includes a predictable flight path, altitude, and route designed to keep the aircraft clear of other traffic and lead it either to a recovery point or to a planned termination of flight.
Plain English
What an unmanned aircraft does on its own when it loses the radio connection to the person flying it from the ground. The aircraft follows steps already loaded into it so other traffic and controllers know where it will go.
Context Anchor
Used in unmanned aircraft operations, especially in operating approvals, mission planning, and coordination with air traffic control.
Derivation
‘Lost link’ simply means the control link has been lost. The phrase is built from everyday words, but in UAS operations it specifically refers to the radio data link between the ground control station and the aircraft — not a chain, cable, or physical connection.
Why Pilots Care
It prevents an uncontrolled aircraft from entering busy airspace or flying until fuel is exhausted, protecting people and property on the ground.
Grounding Statement
If the control connection drops, the aircraft should follow a known safe plan rather than continue unpredictably.
Intuition Check
Do not read “lost link” as the aircraft being lost or off course. It means the control connection has been lost.
Example Sentence 1
When the ground station lost contact with the drone, it began climbing to its lost link altitude and tracking toward the recovery point as planned.
Example Sentence 2
After ten seconds without uplink, the aircraft automatically began its lost link procedure and headed back to the recovery point at 400 feet.